Following exercise, best spirometry values for each interval are compared to baseline values. Exercise response was defined as the greatest decrease in FEV1 expressed as a percentage of the baseline values. A bronchoconstriction response to exercise is considered as positive when the FEV1 decrease from baseline was greater than 13% [4]. Student’s paired t-test is used for comparison of data between each spirometry index and the calculated values for healthy children. A value of p<0.05 was considered significant.